Catheter Assembly Including a Multi-Lumen Configuration

ABSTRACT

A catheter assembly for use in accessing a vasculature of a patient is disclosed. In one embodiment, the catheter assembly includes a catheter body that includes a flattened oval outer surface and defines first and second lumens. The catheter body defines a distal tip region that includes a venous lateral opening that is in fluid communication with the first lumen and includes a distal-facing portion. The distal tip region further includes an arterial lateral opening that is in fluid communication with the second lumen, includes a distal-facing portion, and is substantially un-staggered with respect to the venous lateral opening. A distal end opening is in fluid communication with a power injectable third lumen. In another embodiment, the first and second lumens each generally include a reniform cross-sectional shape. In yet another embodiment, a dual-lumen catheter includes first and second lumens that each define a modified ellipse cross-sectional shape.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.15/442,608, now U.S. Pat. No. 10,518,064, which is a division of U.S.patent application Ser. No. 14/549,941, filed Nov. 21, 2014, now U.S.Pat. No. 9,579,485, which claims the benefit of U.S. ProvisionalApplication No. 61/907,344, filed Nov. 21, 2013, and which is acontinuation-in-part of U.S. patent application Ser. No. 13/329,156,filed Dec. 16, 2011, now U.S. Pat. No. 8,894,601, which is acontinuation of U.S. patent application Ser. No. 12/262,820, filed Oct.31, 2008, now U.S. Pat. No. 8,092,415, which claims the benefit of U.S.Provisional Application No. 60/984,661, filed Nov. 1, 2007. Each of theaforementioned applications is incorporated by reference in its entiretyinto this application.

BRIEF SUMMARY

Briefly summarized, embodiments of the present invention are directed toa catheter assembly for use in accessing a vasculature or other vesselof a patient during renal replacement or other suitable therapies. Inone embodiment, the catheter assembly includes a catheter body thatdefines at least first and second lumens. The catheter body defines adistal tip region that includes at least one venous lateral opening thatis in fluid communication with the first lumen and includes adistal-facing portion, and at least one arterial lateral opening that isin fluid communication with the second lumen and includes adistal-facing portion. The at least one arterial lateral opening isopposingly positioned in a substantially un-staggered configuration withrespect to the at least one venous lateral opening. A distal end openingis defined on the distal tip region and is sized to pass a fluidtherethrough. In one embodiment, the distal end opening is in fluidcommunication with a third lumen of the catheter body that can withstandhigh fluid flow rates associated with power injection of contrast media,for instance.

In another embodiment, a catheter assembly including a catheter bodydefining a first lumen and a second lumen is disclosed. The catheterbody includes a distal tip region, which in turn includes a nose portionthat defines a distally converging outer surface. A venous lateralopening, in fluid communication with the first lumen, is partiallydefined on the distally converging outer diameter. An arterial lateralopening, in fluid communication with the second lumen, is also partiallydefined on the distally converging outer diameter. The venous andarterial lateral openings are symmetrically disposed in a substantiallyun-staggered position with respect to one another. The distal tipportion further includes a distal end opening in fluid communicationwith one of the venous and arterial lumens and is sized to pass aguidewire therethrough.

In yet another embodiment, the first and second lumens each generallyinclude a reniform cross sectional shape, while the third lumen issubstantially round, interposed between the first and second lumens, andis power injectable.

These and other features of the present invention will become more fullyapparent from the following description and appended claims, or may belearned by the practice of the invention as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify the above and other advantages and features of thepresent invention, a more particular description of the invention willbe rendered by reference to specific embodiments thereof that areillustrated in the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope. The invention willbe described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 is a perspective view of a catheter assembly incorporatingvarious features of an embodiment of the present invention;

FIG. 1A is a perspective view of another example of a catheter assemblyconfigured according to one embodiment;

FIG. 2 is a perspective view of a distal tip region of the catheterassembly shown in FIG. 1, configured according to one embodiment;

FIG. 3 is a side view of the catheter distal tip region of FIG. 2;

FIG. 4 is a top view of the catheter distal tip region of FIG. 2;

FIG. 5 is an end view of the catheter distal tip region of FIG. 2;

FIG. 6 is a perspective view of the catheter distal tip region of FIG.2, depicting various details of lateral openings defined therein;

FIG. 7A is a cross sectional view of the catheter assembly and distaltip region of FIG. 2, showing the flow of blood therethrough in a“forward” flow configuration;

FIG. 7B is a cross sectional view of the catheter assembly and distaltip region of FIG. 2, showing the flow of blood therethrough in a“reverse” flow configuration;

FIG. 8A is a cross sectional view of the catheter assembly, taken alongthe line 8A-8A in FIG. 4;

FIG. 8B is another cross sectional view of the catheter tip, taken alongthe line 8B-8B in FIG. 4;

FIG. 8C is yet another cross sectional view of the catheter tip, takenalong the line 8C-8C in FIG. 4;

FIG. 8D is yet another cross sectional view of a distal tip region ofthe catheter assembly showing positioning of a third lumen thereof inaccordance with one embodiment;

FIGS. 9A-9F depict various views of a catheter assembly including adistal tip region configured in accordance with one embodiment;

FIGS. 10A-10D are perspective, front, side, and top views, respectively,of a catheter including a distal tip region configured in accordancewith one embodiment;

FIGS. 11A-11D are perspective, front, side, and top views, respectively,of a catheter including a distal tip region configured in accordancewith one embodiment;

FIGS. 12A-12D are perspective, front, side, and top views, respectively,of a catheter including a distal tip region configured in accordancewith one embodiment;

FIGS. 13A-13D are perspective, front, side, and top views, respectively,of a catheter including a distal tip region configured in accordancewith one embodiment;

FIGS. 14A-14D are perspective, front, side, and top views, respectively,of a catheter including a distal tip region configured in accordancewith one embodiment;

FIGS. 15A-15D are perspective, front, side, and top views, respectively,of a catheter including a distal tip region configured in accordancewith one embodiment;

FIGS. 16A-16D are perspective, front, side, and top views, respectively,of a catheter including a distal tip region configured in accordancewith one embodiment;

FIGS. 17A-17D are perspective, front, side, and top views, respectively,of a catheter including a distal tip region configured in accordancewith one embodiment;

FIGS. 18A-18D are perspective, front, side, and top views, respectively,of a catheter including a distal tip region configured in accordancewith one embodiment;

FIGS. 19A-19D are perspective, front, side, and top views, respectively,of a catheter including a distal tip region configured in accordancewith one embodiment;

FIGS. 20A-20D are perspective, front, side, and top views, respectively,of a catheter including a distal tip region configured in accordancewith one embodiment;

FIG. 21 is a perspective view of a catheter assembly according to oneembodiment;

FIGS. 22A and 22B are various perspective views of a distal portion ofthe catheter assembly of FIG. 21;

FIGS. 23A-23C are various cross-sectional views of the distal portion ofthe catheter assembly of FIG. 21;

FIG. 24 is a cross-sectional view of the catheter assembly of FIG. 21;

FIG. 25 is a cross-sectional view of a catheter assembly according toone embodiment;

FIG. 26 is a cross-sectional view of a catheter assembly according toone embodiment;

FIG. 27 is a perspective view of a catheter assembly according to oneembodiment; and

FIG. 28 is a cross-sectional view of the catheter assembly of FIG. 27.

DETAILED DESCRIPTION OF SELECTED EMBODIMENTS

Reference will now be made to figures wherein like structures will beprovided with like reference designations. It is understood that thedrawings are diagrammatic and schematic representations of exampleembodiments, and are not limiting of the embodiments nor are theynecessarily drawn to scale.

For clarity it is to be understood that the word “proximal” refers to adirection relatively closer to a clinician using the device to bedescribed herein, while the word “distal” refers to a directionrelatively further from the clinician. For example, the end of acatheter placed within the body of a patient is considered a distal endof the catheter, while the catheter end remaining outside the body is aproximal end of the catheter. Also, the words “including,” “has,” and“having,” as used herein, including the claims, shall have the samemeaning as the word “comprising.”

FIGS. 1-20D depict various features of embodiments of the presentinvention, which are generally directed to an acute catheter assemblyfor use in accessing a vasculature or other vessel of a patient duringrenal replacement therapies such as hemodialysis or blood purification,though the principles of the present invention may be extended to othercatheters employed in other uses in addition to these. Such acutecatheters are typically employed in short-term placement scenarios suchas a placement of less than 30 days, though the principles to bedescribed herein can also apply to mid-term and long term catheterplacements as well.

In accordance with one example embodiment, the catheter assemblyincludes a distal tip region defining separate venous and arteriallateral openings, in fluid communication with corresponding venous andarterial lumens that are employed for simultaneously infusing andaspirating blood from a vein or other vessel of a patient's vasculatureduring hemodialysis treatments. The venous and arterial lateral openingsare disposed in a substantially equivalent, non-staggered position withrespect to one another so as to enable positioning thereof in apredetermined region of the vasculature. This notwithstanding, thelateral openings are configured to reduce the likelihood ofrecirculation by the arterial segment of treated blood just returned tothe vessel by the venous segment, thus increasing catheter efficiency.Moreover, the lateral openings can be operated in a reverse flowconfiguration without significantly impacting catheter efficiency duringhemodialysis.

Embodiments of the catheter assembly to be described herein furtherinclude a distal end opening in fluid communication with a lumen of thecatheter configured to withstand relatively high pressure and flow ratestypically associated with power injection. This enables aspiration orinfusion of fluids to occur via this lumen independently of the venousand arterial lumens. “Power injection” is defined herein to includefluid infusion under relatively high flow rates and/or relatively highpressures. For instance, in one embodiment power injection includesfluid infusion through a catheter lumen at a flow rate of between aboutthree and about eight milliliters per second, and/or at a pressure ofbetween about 50 and about 250 psi.

For clarity it is to be understood that the word “proximal” refers to adirection relatively closer to a clinician using the device to bedescribed herein, while the word “distal” refers to a directionrelatively further from the clinician. For example, the end of acatheter placed within the body of a patient is considered a distal endof the catheter, while the catheter end remaining outside the body is aproximal end of the catheter. Further, the words “including,” “has,” and“having,” as used herein, including the claims, shall have the samemeaning as the word “comprising.”

Reference is first made to FIG. 1, which depicts various features of ahemodialysis catheter assembly, generally designated at 10, according toone example embodiment. As shown, the catheter 10 includes an elongatecatheter body 11 including a proximal end 11A and a distal end 11B. Theelongate catheter body 11 defines a first lumen 12, a second lumen 14,and a third lumen 15 (FIG. 7A) that longitudinally extend from theproximal end 11A to the distal end 11B thereof. The lumens 12, 14, and15 can have one or more cross sectional shapes along their respectivelengths, including round, oval, D-cross sectional shapes, or anycombination thereof. In one embodiment, the first and second lumens 12,14 are sized so as to accommodate fluid flow rates required forhemodialysis, i.e., about 300 milliliters/min. at about 250 millimetersHg pressure. In one embodiment, the third lumen is sized with a diameterof about 0.035 to about 0.038 inch to accommodate blood draws and fluidaspiration/infusion therethrough.

A trifurcating hub 20 is included at the catheter body proximal end 11A,providing fluid communication between the first, second, and thirdlumens 12, 14, 15 and arterial extension leg 16, venous extension leg18, and power extension leg 19, respectively. The extension legs 16, 18,19 each include a luer connector 16A, 18A, 19A, and a clamp 16B, 18B,19B. So configured, the extension legs 16, 18 provide fluidcommunication with the first and second lumens 12 and 14 so as to enablethe infusion or aspiration of fluids from the central venous system of apatient. As such, fluid infusion or aspiration devices, such as ahemodialysis apparatus for example, may be connected to the catheterassembly 10 via the luer connectors 16A, 18A, thus providingintravascular access to the patient. Similarly, the extension leg 19provides fluid communication with the third lumen 15 to enable fluidinfusion/aspiration from the vein when a corresponding device isconnected thereto via the connector 19A. Note that the respectivepositions and configurations of the extension legs detailed here canchange according to a particular catheter assembly design and thereforenot be viewed as limiting. The catheter body 11 further includes asuture wing 21 for providing securement of the catheter body to thepatient.

FIG. 2 shows the catheter assembly 10 according to another exampleembodiment, wherein the extension legs 16, 18 each include a pre-curvedportion 16C, 18C. The pre-curved portions 16C, 18C enable the extensionlegs 16, 18 of the catheter assembly 10 to extend downward against thepatient's body once the distal portion of the catheter assembly has beenplaced in the vasculature to provide patient comfort.

In greater detail, the power extension leg 19 of FIGS. 1 and 2 fluidlyconnects to the third lumen 15 via the trifurcating hub 20. Inparticular, the power extension leg 19 is configured in one embodimentto enable rapid infusion, i.e., power injection, of contrast media,useful for contrast-enhanced CT scan imaging, or other fluids into thepatient vessel via the third lumen 15. Specifically, in one embodiment,the power extension leg 19 and third lumen 15 are configured to infusefluids at a rate of between about 3 milliliters and about 8 millilitersper second and at a fluid pressure of between about 50 and 250 psi,though other flow rates and fluid pressures may also be possible. Thepower extension leg 19 and third lumen 15 can also be used to removeblood or other fluids alone or during simultaneous use of the first andsecond lumens 12 and 14, and to monitor central venous pressure with theassistance of a transducer. The power extension leg 19 and third lumen15 are also sufficiently sized to receive a guidewire therethrough toenable insertion of the catheter assembly over the guidewire. Note thatthe components of the power extension leg 19 are colored purple in oneembodiment to indicate power injectability. Other colors could also beused.

Both FIGS. 1 and 2 further include a distal tip region, generallydesignated at 50, that is configured in accordance one exampleembodiment of the present invention, the details of which are givenbelow. It should be appreciated that the distal tip region to bedescribed below can be included with hemodialysis catheters, such asthose shown in FIGS. 1 and 2, or with other catheters, such as centralvenous catheters, for example. Indeed, the catheter assembly accordingto embodiments of the present invention can be adapted for use in otherapplications, such as chronic dialysis treatment, or where access isdesired to be gained to a vessel, such as the internal jugular,subclavian, or femoral vessels, or other body lumen of a patient.Examples of such other applications include apheresis, hemoperfusion,etc.

Reference is now made to FIGS. 2-6, which show various views of a distaltip region, generally designated at 50, of the catheter assembly 10 andconfigured according to one example embodiment. In detail, the distaltip region 50 generally includes a terminal catheter portion 50A and anose portion 50B disposed distally of the terminal catheter portion todefine a distal end of the catheter assembly 10. The terminal catheterportion 50A, as part of the more proximal portion of the catheter body11, is composed of suitable material(s) that exhibit qualities, such assuitable softness to allow for ease of insertion without causing vesseltrauma, and biocompatibility for enabling the catheter to operate asintended. In one embodiment, the catheter body 11 is composed ofmaterial(s) including a thermoplastic polyurethane-based resin material,specifically a polyether-based, aliphatic thermoplastic polyurethanesold under the trademark TECOFLEX, namely TECOFLEX EG-60D-B20, having aShore D hardness of approximately 60, where “B20” refers to theradiopacifier loading, i.e., barium sulfate loading at 20%. Othersuitable materials can also be employed.

In contrast, the nose portion 50B includes a material relatively softerthan that of the terminal catheter portion 50A so as to prevent the tipportion from damaging the vessel or other vasculature during vesselentry or transit. In one embodiment, the nose portion 50B is composed ofmaterial(s) including TECOFLEX EG-85A-B20 having a Shore A hardness ofapproximately 85. Notwithstanding the above description, it should beappreciated that the terminal catheter portion and the nose portion caninclude other materials having the desired properties as describedherein and as appreciated by one skilled in the art. One non-limitingexample of material that can be used for the terminal catheter portionand nose portion is silicone.

Note that in the illustrated embodiment, the nose portion 50B is joinedto the terminal catheter portion 50A via a molding process duringmanufacture of the catheter assembly 10. In other embodiments, however,other processes for joining the nose portion to the catheter body can beemployed, including for instance RF fusion (RF tipping), bonding viaadhesive, integrally forming the nose portion with the catheter body,etc.

As best seen in FIGS. 3 and 4, the nose portion 50B is distallyconverging. In the present embodiment, the nose portion 50B is taperedso as to ease entry and passage of a distal portion of the catheter body11 into the vasculature or other internal cavity of a patient. The noseportion 50B may be colored differently from the remainder of thecatheter body 11 to indicate that the catheter assembly 10 can beemployed for relatively rapid fluid aspiration and infusion via thethird lumen 15 and corresponding power extension leg 19, as wasdescribed further above.

The distal tip region 50 includes various openings for enabling theinfusion and aspiration of fluids while the catheter assembly 10 isplaced for use within the patient vasculature. Specifically, and inaccordance with one embodiment, the distal tip region includes a venouslateral opening 60, an arterial lateral opening 62, and a distal endopening 64.

In greater detail, the venous and arterial lateral openings 60 and 62are positioned opposite one another proximate the catheter body distalend 11B and are defined in a lateral portion of an outer wall of thecatheter body 11 so as to be in fluid communication with first lumen 12and the second lumen 14, respectively, thus enabling blood or otherfluids to flow via the openings to/from the lumens when the catheterassembly 10 is positioned within the patient's vasculature. The venousand arterial lateral openings 60 and 62 are defined by perimeters 60Aand 62A, respectively, as best seen in FIG. 4 and described furtherbelow.

Note that each of the lateral openings 60 and 62 distally extends fromthe terminal catheter portion 50A into the nose portion 50B. Of course,the exact placement of the lateral openings 60 and 62 along thelongitudinal length of the catheter body 11 can vary according the needsof a particular application.

FIG. 4 shows that in the present embodiment the venous and arteriallateral openings 60 and 62 are substantially un-staggered, i.e., equallyplaced with respect to one another along the longitudinal length of thecatheter body 11 such that each is substantially disposed an equaldistance from the distal catheter end 11B. Such un-staggered disposal ofthe lateral openings 60 and 62 enables both openings to be placedproximate a desired location within the vasculature and ensures that therecirculation rate of already treated blood through the catheterassembly 10 is held relatively constant regardless the respectivedirections of blood travel in/out of the lateral openings. This featureis useful should reversal of blood flow directions through the catheterbe necessary. In one embodiment, the recirculation rate in eitherdirection is less than or equal to about five percent. In anotherembodiment, the venous and lateral openings can be staggered.

FIGS. 2-6 further show the manner in which the venous and lateralopenings 60 and 62 are defined in the distal tip region 50. The lateralopenings 60 and 62 can take various shapes and configurations as will beshown further below, but in the present embodiment the lateral openingsare defined by angled cross-drilled cuts through the outer wall of thecatheter body 11 to establish communication with the respective first orsecond lumens 12, 14. In one embodiment, such cuts are referred to as“skive” cuts.

In one embodiment, a long axis of each cross-drilled cut of the lateralopenings 60, 62 defines in one embodiment an angle θ₁ of about 35degrees with a longitudinal axis of the catheter body 11, though thisangle can vary in one embodiment from about greater than zero to about90 degrees. This angular character imparts both a lateral and distaldirectional component to fluid flow out of either lateral opening 60,62, as represented by the flow arrows in FIG. 4, which assists inenabling low-recirculation fluid flow out of or into either lateralopening. Each lateral opening 60 and 62 in the present embodiment isdefined by identical cross cuts having the same angle θ₁ with respect tothe longitudinal axis 70, though it is also possible to vary the anglegenerally, or to vary the angle differently for each opening.

In one embodiment, the lateral openings can be defined by acompound-angle cross cut, wherein the long axis of each lateral openingdefines an angle with the catheter body longitudinal axis and with aplane dividing the first lumen and the second lumen, i.e., coplanar withthe septum separating the first and second lumens proximal of the distaltip region.

An end view of the cross cut, depicted in FIG. 6, shows that the crosscut of each opening 60 and 62 in the illustrated embodiment is made soas to generally define a semicircular cavity through a peripheralportion of the distal tip region 50. This cavity is defined by a portionof a circle 72 having a radius “R,” shown in FIG. 6. In the presentembodiment, the cross cut that defines the lateral openings 60 or 62 isachieved via use of a cylindrical drill bit or coring tool having aradius equal to the radius R of the circle 72 and cutting through thedistal tip region 50 set at the angle θ₁. For instance, in oneembodiment a drill bit having a radius of 1/16 inch is used todiagonally cross cut the venous and arterial lateral openings 60 and 62through a catheter body defining an oblong cross section, wherein theaverage of the major and minor diameters is approximately 0.173 inches.Note that the catheter body size in one embodiment can vary from 7-16Fr., though other French sizes are also possible. Though shown inconnection with the venous lateral opening 60, the above descriptionapplies to the arterial opening 62 as well. Note here that, thoughidentically sized and shaped in the present embodiment, the first andsecond openings could have respectively differing dimensions if desiredor needed for a particular application.

As a result of defining the cross cuts as just described, the venous andarterial openings 60 and 62 are defined by their respective perimeters60A and 62A discussed above. The angle at which the cross cuts are made,together with the shape of the catheter body 11 at the point of thecuts, results in the perimeters 60A and 62A shaped as seen in theaccompanying figures. As best seen in FIG. 4, each perimeter 60A and 62Adefines in the present embodiment a figure-eight shape, or analemma,when viewed in a two-dimensional perspective and an elongate saddleshape when viewed in a three-dimensional perspective. Further, because adistal portion of each opening 60 and 62 is defined on a portion of thetapered nose portion 50B (best seen in FIGS. 4 and 5), each opening hasa distal-facing component, best seen in FIG. 5, wherein a portion eachlateral opening is distally visible.

The configuration of the venous and arterial lateral openings 60 and 62described above provides various aspects for the catheter assembly 10.First, because of their saddle shapes, the lateral openings 60 and 62partially extend circumferentially about the outer perimeter of thecatheter body 11. This helps to prevent undesired suctioning of thedistal tip region 50 to the vessel wall when one of the openings isremoving blood from the vessel as the negative flow pressure of theopening is distributed about a portion of the catheter bodycircumference. If vessel suck-up does occur, the lateral openings 60, 62are shaped so as to nonetheless provide acceptable fluid flow in and outof the catheter assembly 10. The relatively large size of the lateralopenings 60 and 62 also assists in the prevention of occlusion or sheathformation and provides a fanned-out or wide distribution of fluidflowing out therefrom. Recirculation efficiency rates are improved as aresult.

Second, the distal-facing aspect of each lateral opening 60 and 62assists in imparting a distal direction to fluids being ejectedtherefrom. This enables the ejected fluid to distally flow away from onerespective lateral opening and distal-to proximal flow into the otherlateral opening even when the catheter body 11 is positioned against avessel wall. In addition, the lateral openings 60, 62 are symmetricallyopposed, in direction from one another, i.e., a 180-degree separation asbest shown in FIG. 4, so as to ensure fluid entry and exit from thelateral openings occurs on opposite sides of catheter assembly 10,further reducing recirculation. Furthermore, this symmetric positioningproduces a “criss-cross” relationship between the lateral openings 60and 62, as best seen in FIG. 3, which assists in reducing recirculation.Moreover, similar fluid flow characteristics are realized even whenfluid flow through the catheter assembly 10 is reversed, as discussedfurther below. In addition, the lateral opening configuration describedherein minimizes radical redirection of the fluid upon exiting thecatheter body 11 via either of the lateral openings 60 or 62, which inturn prevents fluid turbulence and possible clotting or hemolysis.

As shown in FIGS. 2-6, the distal end opening 64 is distally located atthe distal end of the distal tip region nose portion 50 and is in fluidcommunication with the third lumen 15 so as to enable high flow rateinfusion, i.e., power injection of contrast media or other fluids suchas TPN nutritional fluid and medications into the vessel, as well as theremoval of blood from the vessel during catheter use. In the case ofinfusion of contrast media or medications into the vessel, placement ofthe distal end opening 64 distally of the first and second openings 60and 62 advantageously results in minimization of contrastmedia/medication intake into either of the first or second openings ifthe infusion takes place simultaneously with fluid passage through thevenous and arterial openings 60 and 62, such as during hemodialysis orother treatments.

Note that, in one embodiment a guidewire can be inserted through thedistal end opening 64, the third lumen 15, and the power extension leg19 during initial or exchange catheter placement in the patientvasculature. Also note that the relatively proximate placement of thethree openings 60, 62, and 64 in the distal portion of the catheter body11 enables each opening to be placed near desired location within thevasculature, such as the superior vena cava (“SVC”).

Reference is now made to FIGS. 7A and 7B in describing flowcharacteristics with respect to the configuration of the distal tipregion 50 of the catheter assembly 10 according to the presentembodiment. FIGS. 7A and 7B show the distal tip region 50 after thecatheter assembly 10 has properly positioned within a vessel of apatient. Arrow 84 shows the direction of blood flow past the distal tipregion 50 within the patient's vessel.

In greater detail, FIG. 7A shows fluid flow through the distal tipregion 50 in a “forward” direction, wherein blood is aspirated by thesecond lumen 14, or “uptake” lumen, for removal from the body andtreatment by a hemodialysis apparatus or for some other suitablepurpose. Aspirated blood enters the second lumen 14 via the arteriallateral opening 62 of the distal tip region 50. Similarly, blood isinfused, or returned, to the vessel by the first lumen 12, or “return”lumen, after treatment by a hemodialysis apparatus or some othersuitable purpose. Infused blood exits the first lumen 12 from the venouslateral opening 60. Note that the lateral orientation of the venous andarterial lateral openings 60, 62 provides for low recirculation ofalready-treated blood within the vessel, recirculation being defined asalready-treated blood that is returned to the bloodstream via the venouslumen being immediately aspirated by the arterial lumen to bere-treated. Such recirculation is undesirable as it results in lowertreatment efficiency, resulting in longer treatment time.

During hemodialysis procedures, it is sometimes necessary to reverse theblood flow through the catheter assembly 10. FIG. 7B shows fluid flowthrough the distal tip region 50 during such a “reverse” flow situation.In contrast to the forward flow conditions of FIG. 7A, the second lumen14 in FIG. 7B is employed to infuse blood into the vessel while thefirst lumen 12 aspirates blood from the vessel. In this configuration,the infused blood enters the vessel via the arterial lateral opening 62,while the aspirated blood is removed via the venous lateral opening 60.Again, the lateral orientation of the venous and arterial lateralopenings 60, 62 provides for low recirculation of already-treated bloodwithin the vessel. Thus, it is seen that low recirculation resultsregardless of the direction in which the catheter is operating.

FIGS. 7A and 7B further show that fluid can be aspirated or infused viathe distal end opening 64 in fluid communication with the third lumen 15before, after, or during infusion/aspiration by the venous and arteriallateral openings 60, 62. As mentioned, the third lumen 15 and distal endopening 64 are configured so as to withstand relatively high pressurizedfluid flow infusion into the vessel. It is appreciated that in otherembodiments, more than one of the catheter lumens can be configured forhigh pressurized fluid flow infusion, if desired.

It should be appreciated that the labels “venous” and “arterial” as usedabove in describing the various components of the present catheterassembly are employed for sake of convenience in describing aspects ofpresent embodiments. Indeed and as just described, though the arteriallateral opening is normally employed in hemodialysis procedures foraspirating blood from the blood vessel in which the catheter is disposedand the venous lateral opening for returning already treated blood tothe vessel, this can be reversed such that blood is returned via thearterial lateral opening and aspirated by the venous lateral opening. Assuch, embodiments of the present invention should not be consideredlimited by the use of this and other descriptive terminology herein.

Reference is now made to FIGS. 8A-8C, which depict various detailsregarding the catheter body 11. In detail, FIG. 8A shows a crosssectional view of the catheter body 11 at a point proximal to the distaltip region 50, showing the first lumen 12, the second lumen 14, and thethird lumen 15. The three lumens 12, 14, 15 are defined along thelongitudinal length of the catheter body 11 and bounded by an outerperimeter or wall 86. The outer wall 86 of the catheter body 11 in thepresent embodiment defines an oblong shape and includes a transverseaxis 88 that intersects the first and second lumens 12, 14 and spans thewidth of the catheter body. Placement of the first and second lumens 12,14 adjacent one another, with the third lumen 15 positioned therebelow,provides a robust lumen configuration that resists inadvertent closureof lumens via kinking of the catheter body 11. In addition, the oblongcross sectional configuration of the catheter body 11 enables circularcross sectional shapes to be employed for the lumens 12, 14, and 15,which are relatively more efficient than “D”-shaped or other shapedlumens in terms of fluid flow.

As seen in FIG. 8B and as previously described, the venous lateralopening 60 is defined so that it intercepts the first lumen 12, whilethe arterial lateral opening is defined so that it intercepts the secondlumen 14. As such, the first lumen 12 establishes fluid communicationbetween the venous extension leg 18 and the venous lateral opening 60,while the second lumen 14 establishes fluid communication between thearterial extension leg 16 and the arterial lateral opening 62. In oneembodiment, the angled cross cuts that define the venous and arterialopenings 60 and 62 are made tangentially with respect to a septum 90separating the first and second lumens 12, 14 such that the septum wallremains intact as a barrier between the two lumens.

FIGS. 8A-8C successively depict the manner in which the third lumen israised from a bottom-central location along the length of the catheterbody 11 to a central position upon its exit at the distal end opening64, as shown in FIG. 5. Of course, other lumen position configurationsare also possible.

It is appreciated that various modifications may be made to the catheterassembly configurations described above. It is noted that for purposesof clarity, only selected differences between the foregoing andfollowing embodiments are described. For instance, FIGS. 9A-9F depict adistal tip region 150 including a terminal catheter portion 150Aintegrally formed with the catheter body 11 and a nose portion 150Bincluding a relatively low hardness, e.g., soft, material and joined tothe terminal catheter portion 150A in a manner similar to that alreadydescribed above in connection with FIGS. 2-6.

The distal tip region 150 defines a venous lateral opening 160 in fluidcommunication with the first lumen 12 and an arterial lateral opening162 in fluid communication with the second lumen 14. A distal endopening 164 is also defined at a distal end of the nose portion 150B.The catheter assembly as configured in FIGS. 9A-9F is a dual lumendevice in that it includes only two lumens 12 and 14 (FIG. 9E). As bestseen in FIG. 9F, therefore, the distal end opening 164 does notcommunicate with a third lumen, but rather with a guidewire channel 164Adefined by the nose portion 150B, which in turn communicates with thefirst lumen 12. In this way, a guidewire pathway is established throughthe catheter body 11 and distal tip region 150 to enable the catheterassembly to be inserted over a guidewire during initial placement andcatheter exchange procedures.

FIG. 9E depicts a cross sectional view of the catheter body proximal ofthe distal tip region 150. As shown, top and bottom portions of an outerwall 186 of the catheter body 11 include thickened regions 186A, whichprovide added kink resistance to the catheter body.

By virtue of its communication with the first lumen 12, the guidewirechannel 164A provides an added fluid outlet/inlet for the first lumenvia the distal end opening 164, thus providing an additional fluidpathway that further reduces recirculation during operation of thecatheter. This fluid communication also maintains the guidewire channel164A patent via the flow of blood therethrough so as to preventocclusion thereof. Further note that, though it is centrally located atthe distal end of the nose portion 150B, the venous lateral opening 164can be positioned such that it and the corresponding guidewire channel164A are in longitudinal linear alignment with the first lumen 12.Further, the venous lateral opening and the corresponding guidewirechannel can be configured as to be in communication with the secondlumen or both the first and second lumens, if desired.

FIGS. 10A-10D and 11A-11D are further examples of a dual lumen catheterassembly configuration, in accordance with example embodiments thereof.The distal tip regions 250/350 each include a terminal catheter portion250A/350A and a nose portion 250B/350B at which are defined a venouslateral opening 260/360, an arterial lateral opening 262/362, and adistal end opening 264/364. A guidewire channel 264A/364A is definedbetween the distal end opening 264/364 to the first lumen 12 so as to bein communication therewith. As can be seen in comparison, the lateralopenings 260, 262 of FIGS. 10A-10D are differently shaped fromcorresponding lateral openings 360, 362 of FIGS. 11A-11D. Further, thenose portion 250B (FIG. 10A) is distally converging in a taperedconfiguration, whereas the nose portion 350B (FIG. 11A) distallyconverges in a rounded configuration to define a bullet-shape. Note alsothat the venous and arterial lateral openings of the dual lumenembodiments describe herein include distal-facing portions, as best seenin FIGS. 10B and 11B, offering characteristics similar to those outlinedabove in connection with the discussion relating to FIGS. 2-6.

FIGS. 12A-20D depict possible configurations of a catheter assemblydistal tip region including three lumens, according to additionalexample embodiments. As they share aspects with the embodiment describedabove in connection with FIGS. 2-7B, only selected aspects of theembodiments to follow will be discussed below.

FIGS. 12A-12D depicts a catheter assembly distal tip region 450,including a terminal catheter portion 450A and a nose portion 450B. Thedistal tip region 450 further includes a venous lateral opening 460 influid communication with the first lumen 12 and an arterial lateralopening 462 in fluid communication with the second lumen 14. A distalend opening 464 is also defined at a distal end of the nose portion450B. In the present embodiment, the lateral openings 460 and 462 eachdefine a trapezoidal perimeter when viewed from the perspective of FIG.12D, and are symmetrically opposed from one another.

FIGS. 13A-13D depicts a catheter assembly distal tip region 550,including a terminal catheter portion 550A and a nose portion 550B. Thedistal tip region 550 further includes a venous lateral opening 560 influid communication with the first lumen 12 and an arterial lateralopening 562 in fluid communication with the second lumen 14. A distalend opening 564 is also defined at a distal end of the nose portion550B. In the present embodiment, the lateral openings 460 and 462 eachdefine a stepped perimeter when viewed from the perspective of FIG. 13D,and are symmetrically opposed from one another.

FIGS. 14A-14D depict a catheter assembly distal tip region 650,including a terminal catheter portion 650A and a nose portion 650B. Thedistal tip region 650 further includes a venous lateral opening 660 influid communication with the first lumen 12 and an arterial lateralopening 662 in fluid communication with the second lumen 14. A distalend opening 664 is also defined at a distal end of the nose portion 650Band is axially offset from a central axis of the catheter body 11. Inthe present embodiment, the lateral openings 660 and 662 each define anoval perimeter when viewed from the perspective of FIG. 12C, and aresymmetrically opposed from one another, as best seen in FIG. 14D.

FIGS. 15A-15D depict a catheter assembly distal tip region 750,including a terminal catheter portion 750A and a nose portion 750B. Thedistal tip region 750 further includes a venous lateral opening 760 influid communication with the first lumen 12 and an arterial lateralopening 762 in fluid communication with the second lumen 14. A distalend opening 764 is also defined at a distal end of the nose portion 750Band is axially offset from a central axis of the catheter body 11. Inthe present embodiment, the lateral openings 760 and 762 each define anoval perimeter when viewed from the perspective of FIG. 15C, and aresymmetrically opposed from one another, as best seen in FIG. 15D.

FIGS. 16A-16D depict a catheter assembly distal tip region 850,including a venous lateral opening 860 in fluid communication with thefirst lumen 12 and an arterial lateral opening 862 in fluidcommunication with the second lumen 14. A distal end opening 864 is alsodefined at a distal end of the distal tip region 850 and is axiallyoffset from a central axis of the catheter body 11. In the presentembodiment, the lateral openings 860 and 862 are separated by a septum890, and each defines a partial oval perimeter when viewed from theperspective of FIG. 16C, and are symmetrically opposed from one another,as best seen in FIG. 16D.

FIGS. 17A-17D depict a catheter assembly distal tip region 950,including a venous lateral opening 960 in fluid communication with thefirst lumen 12 and an arterial lateral opening 962 in fluidcommunication with the second lumen 14. A distal end opening 964 is alsodefined at a distal end of the distal tip region 850 and is axiallyoffset from a central axis of the catheter body 11. In the presentembodiment, the lateral openings 960 and 962 are separated by a septum990, and each defines an acute angle-shaped perimeter together with aportion of an outer catheter body wall 986 when viewed from theperspective of FIG. 16C. As before, the lateral openings 960, 962 aresymmetrically opposed from one another, as best seen in FIG. 17D.

FIGS. 18A-18D depict a catheter assembly distal tip region 1050,including a terminal catheter portion 1050A and a nose portion 1050B.The distal tip region 1050 further includes a venous lateral opening1060 in fluid communication with the first lumen 12 and an arteriallateral opening 1062 in fluid communication with the second lumen 14. Adistal end opening 1064 is also defined at a distal end of the distaltip region nose portion 1050B and is centrally disposed with respect toa central axis of the catheter body 11. In the present embodiment, thelateral openings 1060 and 1062 are separated by a septum 1090, and eachdefines a partial oval perimeter when viewed from the perspective ofFIG. 18C. As before, the lateral openings 1060, 1062 are symmetricallyopposed from one another, as best seen in FIG. 18D.

FIGS. 19A-19D depicts a catheter assembly distal tip region 1150,including a nose portion 1150B. The distal tip region 1150 furtherincludes a venous lateral opening 1160 in fluid communication with thefirst lumen 12 and an arterial lateral opening 1162 in fluidcommunication with the second lumen 14. A distal end opening 1164 isalso defined at a distal end of the distal tip region 1150 and isaxially offset from a central axis of the catheter body 11. In thepresent embodiment, the lateral openings 1160 and 1162 each define atriangular perimeter when viewed from the perspective of FIG. 19D, andare symmetrically opposed from one another as best seen in FIG. 19D.

FIGS. 20A-20D depict a catheter assembly distal tip region 1250,including a terminal catheter portion 1250A and a nose portion 1250B.The distal tip region 1250 further includes a venous lateral opening1260 in fluid communication with the first lumen 12 and an arteriallateral opening 1262 in fluid communication with the second lumen 14. Adistal opening 1264 is also defined on the nose portion 1250B and isaxially offset from a central axis of the catheter body 11. In thepresent embodiment, the lateral openings 1260 and 1262 are separated bya septum 1290, and each defines a frustoconical perimeter when viewedfrom the perspective of FIG. 20C. As before, the lateral openings 1260,1262 are symmetrically opposed from one another, as best seen in FIG.20D. In addition to the lateral openings 1260, 1262, the terminalcatheter portion 1250A further includes a plurality of venous openings1260A and a plurality of arterial openings 1262A. The openings 1260A,1262A are relatively smaller than the lateral openings 1260, 1262, andare distributed about the perimeter of the catheter body so as tofurther reduce the possibility of vessel wall suck-up.

FIGS. 21-24 depict various details of a catheter assembly 1310 accordingto one embodiment. Note that the embodiments described below includevarious similarities to the embodiments described above; as such, onlyselected aspects will be discussed below.

As shown, the catheter assembly 1310 includes an elongate catheter tube,or catheter body 1311, which defines a plurality of lumens extendingfrom a proximal end 1311A to a distal end 1311B. The proximal end 1311Aof the catheter body 1311 is operably attached to a bifurcation 1320,which in turn is operably attached to extension legs, namely an arterialextension leg 1316, a venous extension leg 1318, and a power extensionleg 1319 suitable for power injection of a fluid therethrough. Thenumber of catheter body lumens, extension legs, and their respectiveconfigurations can vary from what is shown and described herein. Forinstance, though shown in FIG. 21 as straight, the arterial and venousextension legs 1316, 1318 can each be curved in a U-shapedconfiguration, in one embodiment. These and other modifications arecontemplated. Note also that “bifurcation” is understood to include ahub that provide two or more fluid pathways.

With continuing reference to FIG. 21, reference is made to FIGS. 22A and22B, which depict distal portions of the catheter assembly 1310 and itselongate catheter body tube 1311, according to the present embodiment.As shown, the distal portion of the catheter body 1311 includes featuressimilar to those shown in FIGS. 1-5 (discussed further above), includinga tapered distal tip region 1350, in contrast to the cylindricallyflattened oval-shaped outer surface of the more proximal portion of thecatheter body, a venous lateral opening 1360, and an arterial lateralopening 1362. The arterial and venous and arterial lateral openings 1360and 1362 are in fluid communication with respective arterial and venouslumens, which are referenced below and defined by the catheter body1311. Each of the venous and arterial lateral openings 1360 and 1362 isdefined by an angled skive cut so as to impart an angular directioncomponent, with respect to the longitudinal axis of the catheter tube1311, to fluid entering (via the arterial distal opening) or exiting(via the venous distal opening) the catheter tube, as before.

A third lumen distal end opening 1364 is included at the distal end ofthe distal tip region 1350 and is in fluid communication with a thirdlumen defined by the catheter body 1311, as discussed below. Inaddition, side holes 1342 are included in the catheter body 1311proximal to the distal tip region 1350, which are in fluid communicationwith one of the arterial and venous lumens. Such side holes provide analternate fluid path in addition to the venous and arterial lateralopenings 1360, 1362. Note that the particular configuration of thevarious lateral and side hole openings can vary from what is shown anddescribed herein.

FIGS. 23A-23C depict the lumen configuration of the catheter body 1311according to the present embodiment. As shown, an outer perimeter, orouter wall 1386 having a substantially flattened oval cross-sectionalconfiguration defines the external portion of the catheter 1311. Indeed,the outer wall 1386 bounds a first, arterial lumen 1312, a second,venous lumen 1314, and a third lumen 1315, as mentioned above. A septum1390 cooperates with the outer wall 1386 to define the particular shapeconfigurations of the three lumens 1312, 1314, and 1315, which eachsubstantially extend the longitudinal length of the catheter body 1311.FIG. 23B shows the manner in which the arterial lumen 1312 and venouslumen 1314 communicate with the arterial lateral opening 1362 and thevenous lateral opening 1360, while FIG. 23C shows the manner in whichthe third lumen 1315 extends distally toward the distal end opening 1364on the distal tip region 1350.

FIG. 24 depicts further details regarding the cross-sectional lumenconfiguration of the catheter body 1311, according to the presentembodiment. As shown, the flattened oval outer wall 1386 and the septum1390 of the catheter body 1311 define the arterial lumen 1312, thevenous lumen 1314, and the third lumen 1315, as mentioned above. FIG. 24shows that the third lumen 1315 has a cross-sectional shape that issubstantially round and is configured in one embodiment to withstandfluid pressures typically associated with power injection, e.g., about300 psi in one example.

The cross-sectional configurations of the arterial and venous lumens1312, 1314 are mirror projections of each other as taken across thecenter line (“CL”) indicated at 1389 in FIG. 24. In particular, both thearterial and venous lumens 1312, 1314 cross-sectionally define adeformed kidney bean-shaped cross-sectional lumen profile, also referredto herein as a modified reniform shape. In greater detail, each of thearterial and venous lumens 1312, 1314 cross-sectionally defines aconcavely-shaped portion, or concavity 1394, which contributes to thereniform lumen shape. The concavity 1394 for each lumen 1312, 1314 isdisposed above a transverse axis 1388 of the catheter body 1311 as shownin and from the perspective of FIG. 24. Disposal of the concavity 1394of each lumen 1312, 1314 above the transverse axis 1388, as opposed tothe concavity being centered on the transverse axis results in amodified reniform configuration, though it is appreciated that the sizeand location of the concavity can vary from what is shown and describedherein. Indeed, in one embodiment the concavity can be positioned so asto define a general reniform (un-deformed kidney bean) shape.

Each lumen 1312, 1314 further includes an arcuate portion, or major arc1398, opposite the respective concavity 1394 that defines an outerportion of each lumen adjacent the outer wall 1386. The major arc 1398of each lumen 1312, 1314 is bounded on either end by a top corner 1396Aand a bottom corner 1396B. This configuration interposes the top corner1396A between the major arc 1398 and the concavity 1394. The top andbottom corners 1396A and 1396B are substantially rounded to ensure alaminar flow of fluids through the arterial and venous lumens 1312,1314, thus desirably preventing areas of fluid flow stagnation.

As shown in FIG. 24, the septum 1390 is included to separate thearterial lumen, 1312, the venous lumen 1314, and the third lumen 1315.Centered on the center line 1389, the septum 1390 includes a unifiedportion 1390A that generally extends downward from the transverse axis1388 (from the perspective shown in FIG. 24) and a bifurcated portion1390B that generally extends upward from the transverse axis.Particularly, the septum 1390 helps define the aformentioned shapes ofthe lumens. For example, the unified portion 1390A of the septum 1390generally defines an hourglass-like cross-sectional shape to help definethe rounded bottom corners 1396B and the inner portions of both thearterial lumen 1312 and venous lumen 1314, while the bifurcated portion1390B of the septum cooperates with the outer wall 1386 to define thecross-sectional shape of the third lumen 1315 and the concavities 1394of the arterial and venous lumens. Note also that the general hourglassconfiguration of the septum 1390 adds structural strength to the septum.

The cross-sectional configuration shown in FIG. 24 in the presentembodiment extends from the proximal end 1311A of the catheter body 1311distally to the arterial and venous lateral openings 1362, 1360, thoughthis can be modified in other embodiments. It is noted that the variouscross-sectional features of the catheter body 1311 described immediatelyabove can vary in size, shape, and position from what is shown anddescribed herein.

According to one embodiment, the various features described aboveinclude the following cross-sectional dimensions: the perimeter of theouter wall 1386 includes a width of about 0.195 inch and a height ofabout 0.128 inch; the diameter of the third lumen is about 0.040 inch;the thickness of the unified portion 1390A of the septum 1390 is about0.015 inch; the thickness of each branch of the bifurcated portion 1390Bof the septum 1390 at the midpoint of the respective concavity 1394 isabout 0.010 inch; the distance between the outer surface of the outerwall and the nearest point of the third lumen is about 0.010 inch; thethickness of the outer wall at about the midpoint of the major arc 1398is about 0.015 inch; the radius of each concavity of the identicalarterial and venous lumens 1312, 1314 as measured from a center point ofthe third lumen is about 0.030 inch; the radius of each top corner 1396Ais about 0.012 inch; the radius of each bottom corner 1396B is about0.020 inch; the radius of each major arc is about 0.052 inch; the radiusat the end of the concavity opposite the top corner (at about thetransverse axis 1388) is about 0.030 inch; and the distance between theouter surface of the outer wall and the nearest point of arterial orvenous lumen proximate the bottom corner thereof is about 0.010 inch.Note that the lumen configuration of the present embodiment enablesfluid flow therethrough equal to a known 13 French-sized catheter whileoccupying the size of only a 12 French catheter. Of course, the size ofthe catheter body and its respective lumens can be scaled asneeded/desired.

The catheter body 1311 in one embodiment includes a suitablethermoplastic such as polyurethane, for instance. In some embodiments,polyurethane thermoplastics sold under the marks TECOFLEX®, CARBOTHANE®,CHRONOFLEX®, and QUADRIFLEX® can be used to form the catheter tube. Notethat other suitable, biocompatible materials can also be used. In oneembodiment, the catheter tube 12 includes a polyurethane with a 60DShore hardness, which assists in preventing kinking, enabling powerinjection therethrough, and improving insertability into the body of apatient in an acute dialysis scenario, for instance. In othernon-limiting embodiments, the hardness of the catheter tube can varyfrom about 55D to about 65D. Desired characteristics for the materialfrom which the catheter body is formed in one embodiment includethermosensitivity such that the material softens after insertion intothe patient body, and suitable polymer strength to withstand powerinjection pressures to which the catheter assembly may be subjected.

In one embodiment, the atraumatic tip of the distal tip region 1350includes a polyurethane with an 85A Shore hardness. In one non-limitingexample, the atraumatic tip can range from 85A to 75A Shore hardness. Inone embodiment, the material of the catheter body 1311 and atraumatictip can include a radiopaque material, such as barium or tungsten, toenable visibility of the catheter assembly under x-ray imaging.

FIG. 25 depicts the catheter body 1311 according to another embodiment,wherein the arterial and venous lumens 1312, 1314 include a differingcross-sectional configuration from that shown in FIG. 24. As shown, thesubstantially identical arterial and venous lumens 1312, 1314 eachcross-sectionally define the major arc 1398 and opposite thereto aflattened side 1402, defined by the septum 1390.

FIG. 26 depicts the catheter body 1311 according to another embodiment,wherein the arterial and venous lumens 1312, 1314 include a differingcross-sectional configuration from that shown in FIG. 24. As shown, afourth lumen 1410, substantially round in cross-sectional shape, isincluded. Further, the substantially identical arterial and venouslumens 1312, 1314 each cross-sectionally define the major arc 1398 andopposite thereto a convex portion 1414, defined by the septum 1390. Inparticular, the septum 1390 includes a centrally disposed unifiedportion 1390A and a first and second bifurcated portion 1390B, 1390Cthat are disposed on either side of the unified portion and largelydefine the third lumen 1315 and fourth lumen 1410.

FIGS. 27 and 28 depict various details of a catheter assembly 1510according to one embodiment. Note that the embodiments described belowinclude various similarities to the embodiments described above; assuch, only selected aspects will be discussed below.

As shown, the catheter assembly 1510 includes an elongate catheter tube,or catheter body 1511, which defines a plurality of lumens extendingfrom a proximal end to a distal end thereof. The proximal end of thecatheter body 1511 is operably attached to a bifurcation 1520, which inturn is operably attached to extension legs, namely an arterialextension leg 1516 and a venous extension leg 1518. The number ofcatheter body lumens, extension legs, and their respectiveconfigurations can vary from what is shown and described herein. Forinstance, though shown in FIG. 27 as straight, the arterial and venousextension legs 1316, 1318 can each be curved in a U-shapedconfiguration, in one embodiment. These and other modifications arecontemplated.

The distal portion of the catheter body 1511 includes features similarto those shown in FIGS. 1-5 (discussed further above), including atapered distal tip region in contrast to the cylindrically flattenedoval-shaped outer surface of the more proximal portion of the catheterbody, a venous lateral opening 1560, and an arterial lateral opening1562. The venous and arterial lateral openings 1560 and 1562 are influid communication with respective venous and arterial lumens, whichare referenced below and defined by the catheter body 1511. Each of thevenous and arterial lateral openings 1560 and 1562 is defined by anangled skive cut so as to impart an angular direction component, withrespect to the longitudinal axis of the catheter tube 1511, to fluidentering (via the arterial distal opening) or exiting (via the venousdistal opening) the catheter tube, as before.

A distal end opening 1564 is included at the distal end of the distaltip region and is in fluid communication with the venous lumen,described below, though the distal end opening could be in communicationwith the arterial lumen in another embodiment. In addition, side holes1542 are included in the catheter body 1511 proximal to the distal tipregion, which are in fluid communication with one of the arterial andvenous lumens. Such side holes provide an alternate fluid path inaddition to the venous and arterial lateral openings 1560, 1562. Notethat the particular configuration of the various lateral and side holeopenings can vary from what is shown and described herein.

FIG. 28 depicts further details regarding the cross-sectional lumenconfiguration of the catheter body 1511, according to the presentembodiment. As shown, an outer perimeter, or outer wall 1586 having asubstantially flattened oval cross-sectional configuration defines theexternal portion of the catheter 1511. Indeed, the outer wall 1586bounds a first, arterial lumen 1512 and a second, venous lumen 1514, asmentioned above. A septum 1590 cooperates with the outer wall 1586 todefine the particular shape configurations of the two lumens 1512 and1514, which each substantially extend the longitudinal length of thecatheter body 1511. As discussed, the arterial lumen 1512 and the venouslumen 1514 communicate with the arterial lateral opening 1562 and thevenous lateral opening 1560, respectively.

FIG. 28 depicts further details regarding the cross-sectional lumenconfiguration of the catheter body 1511, according to the presentembodiment. As shown, the flattened oval outer wall 1586 and thehourglass-shaped septum 1590 of the catheter body 1511 define thearterial lumen 1512 and the venous lumen 1514, as mentioned above. Thecross-sectional configurations of the arterial and venous lumens 1512,1514 are mirror projections of each other as taken across the centerline (“CL”) indicated at 1389 in FIG. 28. In particular, both thearterial and venous lumens 1512, 1514 cross-sectionally define amodified ellipse cross-sectional lumen profile. In greater detail, eachof the arterial and venous lumens 1512, 1514 cross-sectionally defines afirst, minor arc 1594 adjacent and defined by the hourglass-shapedseptum 1590, bounded by two corners: a top corner 1596A and a bottomcorner 1596B. A second, major arc 1598 extends from each of the corners1596A, 1596B on a side opposite the septum 1590 and adjacent the outerwall 1586 to define the rest of each lumen 1512, 1514. Thisconfiguration interposes both the top corner 1596A and the bottom corner1596B between the major arc 1598 and the minor arc 1594. The top andbottom corners 1596A and 1596B are substantially rounded to ensure alaminar flow of fluids through the arterial and venous lumens 1512,1514, thus desirably preventing areas of fluid flow stagnation.

As shown in FIG. 28, the septum 1590 separates the arterial lumen 1512and the venous lumen 1514. Centered on the center line 1389, the septum1590 defines an hourglass cross-sectional shape equally distributedabout the transverse axis 1388 and helps define the aformentioned shapesof the lumens. Note that the general hourglass configuration of theseptum 1590 adds structural strength to the septum.

The cross-sectional configuration shown in FIG. 28 in the presentembodiment extends from the proximal end of the catheter body 1511distally to the arterial and venous lateral openings 1562, 1560, thoughthis can be modified in other embodiments. It is noted that the variouscross-sectional features of the catheter body 1511 described immediatelyabove can vary in size, shape, and position from what is shown anddescribed herein.

According to one embodiment, the various features described aboveinclude the following cross-sectional dimensions: the perimeter of theouter wall 1386 includes a width of about 0.173 inch and a height ofabout 0.115 inch; the thickness of the septum 1390 at the transverseaxis 1388 is about 0.015 inch; the thickness of outer wall along themajor arc 1598 is about 0.010 inch; the radius of the minor arc 1594 isabout 0.100 inch; the radius of the major arc 1598 is about 0.050 inch;the width of each lumen 1512, 1514 at the transverse axis 1388 is about0.072 inch; and the radius of each corner 1596A, 1596B is about 0.016inch. Note that the above dimensions pertain to a catheter assembly 1510having an 11 French size; of course, the size of the catheter body andits respective lumens can be scaled as needed/desired. The catheter body1511 and its atraumatic tip can include suitable materials as have beendescribed further above.

Embodiments of the present invention may be embodied in other specificforms without departing from its spirit or essential characteristics.The described embodiments are to be considered in all respects only asillustrative, not restrictive. The scope of the embodiments of thepresent invention is, therefore, indicated by the appended claims ratherthan by the foregoing description. All changes that come within themeaning and range of equivalency of the claims are to be embraced withintheir scope.

What is claimed is:
 1. A method for making an elongate catheter tube,the method comprising: extruding an extrusion material to define: anouter surface having a flattened oval cross-sectional shape withopposing flat sides; a first lumen and a second lumen separated by aseptum having an hourglass cross-sectional shape; and a third lumenbetween the first lumen and the second lumen, the third lumen configuredto withstand pressures associated with power injection of a fluidtherethrough.
 2. The method for making according to claim 1, wherein theextruding further comprises defining the first lumen and the secondlumen to each have a cross-sectional shape including: a minor arcportion adjacent the septum; a major arc portion adjacent an outer wallof the catheter tube; and rounded first and second corners interposedbetween the minor arc portion and the major arc portion.
 3. The methodfor making according to claim 2, wherein the extruding comprisesdefining the third lumen to be positioned adjacent the minor arc portionof each of the first lumen and the second lumen.
 4. The method formaking according to claim 1, wherein the extruding comprises defining awall thickness adjacent the major arc portion to be substantiallyconstant.
 5. The method for making according to claim 1, wherein theextruding further comprises defining: a first lateral opening in fluidcommunication with the first lumen, the first lateral opening defined bya first angled cross cut; and a second lateral opening in fluidcommunication with the second lumen, the second lateral opening definedby a second angled cross cut.
 6. The method for making according toclaim 5, wherein the extruding comprises defining the first angled crosscut to include a first cut and a second cut opposite of the first cut,each of the first cut and the second cut having a long axis at anoblique angle with a longitudinal axis of the elongate catheter tube. 7.The method for making according to claim 1, wherein the extrudingfurther comprises defining the first lumen and the second lumen to eachhave a cross-sectional shape including: an arcuate portion; roundedfirst and second corners disposed at either end of the arcuate portion;and a concavity opposite the arcuate portion and interposed between thefirst and second corners.
 8. The method for making according to claim 7,wherein the extruding comprises defining the concavity in an offsetconfiguration with respect to the first and second corners.
 9. Themethod for making according to claim 1, wherein the extruding comprisesdefining the septum to include a unified portion and a bifurcatedportion, the third lumen bounded by the bifurcated portion.
 10. Themethod for making according to claim 1, wherein the extruding comprisesdefining the septum on a center line of the catheter tube such that thefirst and second lumens are disposed in a mirror-image configurationabout the center line.
 11. The method for making according to claim 1,wherein the extruding comprises defining the first lumen and the secondlumen to have substantially identical cross-sectional shapes disposed ina mirror image configuration about the septum.
 12. The method for makingaccording to claim 1, wherein the extruding comprises defining the firstlumen and the second lumen to each have a cross-sectional shapeincluding: a major arc portion adjacent an outer wall of the cathetertube; and flattened side opposite of the major arc portion.
 13. Themethod for making according to claim 1, wherein the extruding comprisesdefining the first lumen and the second lumen to each have across-sectional shape including: a major arc portion adjacent an outerwall of the catheter tube; and a convex portion opposite of the majorarc portion.
 14. The method for making according to claim 13, whereinthe extruding comprises further defining a fourth lumen.
 15. The methodfor making according to claim 14, wherein the extruding comprisesdefining the septum to include a first bifurcated portion, a unifiedportion, and a second bifurcated portion, the third lumen bounded by thefirst bifurcated portion and the fourth lumen bounded by the secondbifurcated portion.
 16. The method for making according to claim 1,wherein the extruding comprises defining a tapered atraumatic distal tipregion.